Paper manufacture.



Patented Mar. l3, I900. F. A. FLETCHER. PAPER MANUFACTURE.

(Application filed Apr. 20, 1899. Renewed Feb. 6, 1900.)

(No Model.)

INVENTOR I ffiwzdAFlek/zw WITNESSES:

ATTORNEY FRANK A. FLETCHER, OF WVATERTOWN, NEW YORK, ASSIGNOR TO THE AERATED PAPER COMPANY, OF NFJV YORK, N. Y.

PAPER MANUFACTURE.

SPECIFICATION forming part of Letters Patent No. 645,081, dated March 13, 1900. Application filed April 20, 1899. Renewed February 6, 1900. Serial No. 4,281. (No model.)

To (tZZ whom it may concern:

Be it known that I, FRANK A. FLETCHER, a citizen of the United States, residing at Watertown, county of Jefferson, State of New York, have invented certain new and useful Improvements in Paper Manufacture, of which the following is a full, clear, and exact description.

My invention relates to a new apparatus for manufacturing paper, and one object is to obtain a paper felt of a soft, porous, and highly-absorbent nature. Another object is to provide an apparatus in which paper-pulp can be taken from a vat, formed into a strip, carried along on a suitable conveyor, such as a belt of wire-cloth, and dried in a rarefied atmosphere, whereby a continuous strip of soft and porous paper is obtained.

The drawing shows a vertical sectional view of the preferred form of apparatus, parts of the same only being indicated.

My paper can be made from almost any kind of paper-stock having a suitable fiber, especially soda pulp. The fiber is reduced into pulp, and as I desire to producea paper 7 which is soft and extremely porous I prefer not to subject the pulp to pressure before I treat it as described hereinafter. In the above embodiment of my invention I have shown my improvement as applied to a cylinder-machineg but I do not desire to limit myself to this form of a machine, and it will be obvious that no particular apparatus for forming the sheet of pulp is necessary.

A is a vat which contains the paper-pulp, a being an inlet for the same and a an outlet for the water from the revolving cylindermold B. This mold is hollow and covered with wire-cloth, and upon it is deposited the paper strip of pulp in a manner well known in this art.

0 is a couch-roll, and D is a roll over which and suitable intermediate supporting or carrying rolls (1 d passes a conveying-belt, in this embodiment consisting of an endless strip of wire-cloth E. The rolls 0 and D and cylinder-mold B are suitably rotated in the direction of the arrows. The paper-pulp strip is formed upon the mold and taken up by the wire'cloth in the manner well understood in .erable.

The Wire-cloth belt allows some of the water in the strip to drain away, and the belt preferably passes over suction-boxes G G, which extract from the strip a portion of the remaining moisture. The belt then passes over a drying means, in this embodiment heatingboxes H, which maybe heated in any desired manner. After leaving the roll D the paper strip may pass onto a separate conveying-belt K, and, if desired, out from the chamber through any suitable air-lock device-such as shown at L.

M are pressing-rolls for the dried paper strip, which may be used, if desired.

As the wire-cloth belt and the strip of paper pass over the heating-boxes the'paper will be partially dried. To accelerate this drying and to produce other advantageous results, I subject the paper strip while still moist to the action of a rarefied atmosphere and preferably to heat at the same time. In the present embodiment I accomplish this by passing the strip of paper through a heated chamber from which the air has been exhausted to any desired degree. As the paper strip comes wet or moist from the vat, I rarefy the air in the chamber N by means of the pump O,which lowers the boiling-point of the water in the strip, and as it passes over the heating-tables this water,or some of it,is preferably turned into steam-bubbles, which force apart the particles of the paper strip and which, if the heat is continued, finally evaporate, producing an extremely-soft, porous, and highlyabsorbent paper.

It is not necessary in forming a soft, porous, and highly-absorbent paper by my process that the heat should be so great as to convert the water in the strip into steam ,because the strip'of paper will have those character- 1 her, means to remove pulp from said vat and istics if the water is evaporated without being converted into steam, although the porosity will be somewhat less than when the steambubbles are formed. 4

Another advantage of rarefying the air in the heating-chamber is that such a high degree of heat is not required to convert the water in the strip into steam or to otherwise evaporate it as would usually be needed. This lessens the danger of injuring the paper strip by a too great heat, which might degrade the color and strength of the product. In this Way I can produce a continuous strip of soft, extremely-porous,anddrypaperwithoutcompressing the same.

The process herein disclosed is claimed in a division of this case, Serial No- 721,810, filed June 26, 1899.

It will be obvious that many changes may be made in the disclosures herein made without departing from the spirit or scope of my invention.

Nhat I claim is- 1. In a paper-machine, a chamber, means to form a sheet of moist paper-pulp in said chamber, means to rarefy and heatthe air in said chamber to drive off moisture from said sheet.

2. In an apparatus for the manufacture of paper,a chamber, a pulp-vat in said chamform the same into a sheet in said chamber, and means to rarefy and heat the air in said chamber to drive off moisture from said sheet and thereby producea soft and porous paper.

3. In an apparatus for the manufacture of paper, a chamber, a movable belt therein, means to apply a paper-pulp to said belt at a point in said chamber to form a strip thereon, means to rarefy the air therein, and meansto substantially dry said strip while in said chamber and before it is compressed.

at. In a paper-machine in combination a substantially closed chamber, a pulp vat therein, a roll in said vat, an endless belt of wire-gauze passing oversaid roll and adapted to pick up said pulp and form the same into a strip thereon, said belt extending through said chamber, means to heat said chamber, means to rarefy the air therein, and means to carry said strip through said chamber so that the same may be dried whereby the porosity of the paper is increased without substantially subjecting the same to pressure, andan airlock exit for said paper from said chamber.

Signed at Watertown, New York, this 18th day of April, 1899.

FRANK A. FLETCHER;

Witnesses:

L. U. HURLBURT, JAMES DOLAN. 

